PCA Patient Controlled Analgesia

In traditional pain management protocols, opioids are administered as protocols, fixed doses at fixed dose intervals or as a fixed-rate infusion; however, fixedthis approach is less than ideal for managing pain. PatientPatient-controlled analgesia (PCA) is a well tolerated and effective method of pain control, especially in the postoperative period.

PCA offers flexibility in dose size and dose interval in individual patients. Patient satisfaction is high with PCA and pain relief is generally better than with conventional therapy, particularly where there is appropriate patient selection and education. Although it was initially thought that less opioid would be used with PCA and that the length of hospital stay would be reduced, this has not been confirmed.

PATIENT CONTROLLED ANALGESIA

Form of systemic opioid therapy Self administered frequent small doses - more closely matches the need of the patient PCA device : microprocessormicroprocessorcontrolled pump Programming the dose, intervals, max. dose per set time and basal rate

? Patient with PCA not need pain treatment ? Same side effects like systematically opioids
.Select the patient
Not too old. too young « Mild to moderate pain Short duration of pain Early postop. period . too confused.

INSTRUCTIONS
NO SYSTEMIC NARCOTICS OR OTHER CNS DEPRESSANTS TO BE GIVEN EXCEPT AS ORDERED BY THE ACUTE PAIN SERVICE.PCA .IV ACCESS ROUTE. NO OTHER INFUSIONS OR MEDICINE MAY BE GIVEN THROUGH THE PCA CONNECTED . PCA NOT TO BE DISCONTINUED EXCEPT BY ACUTE PAIN SERVICE
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.Analgesic requirements variable
There are a number of reasons why patients differ in their opioid requirements:
differing degree of painful stimulus variability in opioid kinetics in the blood variability in the kinetics of CNS uptake of opioids variability in the number and distribution of opioid receptors within the CNS differences in patients' perception of and attitude to their pain accuracy of the infusion device.

has been suggested but only a small number of patients have used the system to date. and a handset that administers a dose of drug when activated by the patient. or it may be a simple disposable pump patientpowered by mechanical means such as a spring or an elastomeric drug reservoir. This may be a microprocessor-controlled system. A `smart pump'. the safety of all systems that give the patient opioid additional to that requested needs to be carefully evaluated. Such systems take some of the control away from the patient. where an infusion is given at a rate proportional to the number of demands made by the patient. As patient control is considered to be fundamental to the safety of PCA. able to implement microprocessorsystem.Device may be simple or complex
A PCA device : a pump with reservoir of drug.
. complex instructions programmed by the prescriber and keep a record of the patient-device interactions.

while the patient determines the timing of the doses Lockout interval must be appropriate Determining appropriate demand dose size Loading with analgesic
.General principles
No benefit from complex dosage regimens .or The clinician decides which drug to use and the size of each dose. .or from background infusions . .

Since there is marked inter-patient variability in the amount of analgesic required for pain relief.
. the loading doses must be titrated to effect.
The loading dose should be repeated every 5 -10 minutes so that the effect of the dose is felt before the next dose is administered.Loading dose
The loading dose accelerates attainment of an effective blood level of the opioid at the initiation of therapy. Many studies have demonstrated a five-fold variability in the quality of IV opioid required to produce equivalent analgesia after surgery.

There are a number of reports every year of patients put at risk by mistakes made by staff when initiating PCA. The risk is increased when the patient's degree of control over drug administration is reduced.Problems with PCA
The risk of serious adverse events associated with PCA is low.
. such as when a background infusion is added.

.Risk of respiratory depression
 background infusions  PCA use in the elderly  concomitant sedative medications  a large demand dose with a short lockout interval.

or have a RR less than the age-appropriate baseline as noted on pediatric order sheet. followed by the addition or adjustment of drug !
y If sedation score = 3 and respiratory rate = 10: Administer oxygen and halve the size of the PCA dose y If sedation score = 3 and respiratory rate <10: STOP PCA. obtain Naloxone 0. Naxolone dose for reversal of respiratory depression with pediatric patients is 2 -5 mcg/kg.4 mg/10cc 0. 1-2 minutes until patient is back to his or her normal baseline (titrate to effect) and offer nonopioid analgesic y For children who are somnolent.3 minutes (titrate to effect).
. difficult to arouse. 2 . STOP PCA and call primary service. repeated q.9% NS and inject 1-2 cc q.Sedation and Respiratory Depression
The first action should be to administer oxygen.

Take precautions against medication errors !
Problems do arise from staff errors. Continuous staff training is advised. usually where the patients or visitors mistook the PCA push button for the nurse call button.
PCA manufacturers have responded to these concerns by producing systems that can be customised to default to the settings that are generally used at any particular hospital thus minimising staff programming errors. Accidental overdoses have been reported. and staff should be present whenever the PCA programme is changed.
. or where the patient's spouse took control of the PCA handset.

In general.. pain 24should be assessed at least every 2 to 4 hours.
.Assessment
The timing for assessment of the efficacy of pain relief is dependent upon the situation. During the initial 24-hour postoperative period. the pain intensity should be assessed routinely with vital signs. every 15 minutes). If the patient is in severe pain requiring upward titration of analgesics.g. pain should be assessed approximately 15-30 15minutes after administering parenteral medication and 60 minutes after administering oral medication. pain assessment should be completed frequently (e. If pain is well controlled.

Modify treatment to achieve effective pain control with minimal harm and side effects.
.

1999) or alteration of pain therapy to allow the 1999) patient to be nausea free with pain control . Helmy... 1997) 1999. Because of high incidence of nausea. prophylactic antiemetic therapy is often given (Chen et al. 1999. 1997.. if a dopamine antagonist was given for nausea earlier.


.. opioids stimulate nausea and may require treatment (Cohen et al.Nausea/Vomiting
 Evaluation of postoperative nausea is to ensure stable vital
signs and adequate control of pain . 1998. Gan et al. Wang.. 1992. 1998. 1996. Chung et al. gan et al. the addition of a serotonin antagonist may be more helpful than a second dopamine antagonist. 1996. Pitkanen et al. antagonist. 1996.  Unfortunately. 1996. 1997. For example. 1997) The choice of antinausea agent is driven by patient factors and prior antinausea therapy. 1992..

.. use of reversal agents is indicated (naloxone 0. If respiratory depression persists.. treatment is the same for this side effect. Eriksson1997. 1992.4 mg intramuscular/intravenous). 1993). After causes of sedation other than analgesics have been addressed. Passchier et al.. this dose may need to be repeated and other causes considered. Eriksson-Mjoberg et al.Lethargy/Sedation/Respiratory Depression
Evaluation is paramount to treatment of sedation. If significant overdose of analgesics is suspected. Respiratory depression secondary to opiates is preceded by lethargy and sedation. 1997. 1993). 1992. adjusting the selected pain therapy is required (Kenady et al.

1992.. Gan et al..
With regional analgesia techniques. 1997). treatment of pruritis in the presence of appropriate opioid therapy is with antihistamines and opioid antagonists (Cohen et al.
.Itching/Pruritis
Once allergic reactions have been ruled out. 1997). it may be possible to eliminate the opioid component. 1992.

. Weakness seen with regional techniques should be minimized to allow for ambulation with assistance if desired.Numbness/Weakness
Numbness is not associated with analgesics other than local anesthetics and the cause should be sought. abscess) and the dose adjusted. Numbness in the affected area in the presence of regional analgesia should be evaluated (possible subarachnoid hematoma. Weakness can be seen with analgesics usually in conjunction with other signs of relative overdose.

Myoclonus/Seizures
SeizureSeizure-like activity in the postoperative setting should be evaluated and treated. this is unlikely in the postoperative setting unless a large amount is actually given. are associated with seizures and myoclonus. While very high doses of local anesthetics can cause seizures.
. Some opioids. meperidine in particular.

sleep deprivation and intraoperative medications (H2 blockers.
. opiates).
Evaluations of hallucinations are often decided by "trial and error" techniques.Hallucinations
Hallucinations in the postoperative patient can be due to a variety of causes including change in surroundings. (H2 anticholinergics.

It is more common with mixed opioid agonists/antagonists and antidopaminergic medications.
.Dysphoria
Postoperative dysphoria is unsettling to the patient and family and difficult to evaluate. but it may also require changing of pain management techniques. Sometimes reassurance can be all that is needed.

Urinary Retention
Urinary
retention is a common side effect of pharmacologic pain management and is more common after neuraxial dministration
.

Hypotension from neuraxial opioids alone is unlikely. Short term therapy can be accomplished with vasopressors until the above can be addressed. Hypotension with regional analgesia techniques is common and treated by replenishing fluids and altering the local anesthetic dose.Hypotension
Hypotension due to systemic analgesics is rare and is likely due to hypovolemia and loss of sympathetic drive with appropriate analgesia.
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